Drafting machine



June 5, 1945; c w KEUFFEL ET AL I 2,377,428.

' DRAFTING MACHINE Filed May 7, 1941 3 Sheets-Sheet 1 T l i A TUBA/5Y5 I June 5, 1945- c. w. KEUFFEL ETAL DRAFTIING mcnim:

Filed May 7, 1941 3 Sheets-Sheet 2 U #6 O m wm EWMM m M, w W 5 m w June 5, 1945.

c. w. KEUFFEL ETAL 2,377,428

DRAFTING, MACHINE 3 Sheets-Sheet 3 Filed May 7, 1941 Q Mm ' I 'a nv-rawans B I (rival Em Patented June 5, 1945 DRAFTING MACHINE wan. um,

UNITED STATES PATENT OFFICE of New Jersey Application May 7, 1941, Serial No. 392,238

Claims.

This invention relates generally to parallel motion drafting devices of the kind in which the several tools which the draftsman handles most frequently are embodied, in principle, in one unit to obviate the necessity of a draftsman reaching about for a required tool and thereby enabling the draftsman to keep his attention concentrated directly upon the drawing.

Drafting devices of this character are common in which adjacent ends of two arms are pivoted together, the free end of one arm being anchored to the remote side of a drafting board while the free end of the other arm is provided with a head comprising a protractor and straight-edges which are in fixed angular relation and move about the center of the protractor as an axis. Such straight-edges have heretofore been so associated with the protractor as to be set and locked at any angle of the protractor or to be automatically locked at predetermined intervals. However, the instrumentalities effecting the setting of the straight-edges with respect to readings on the protractor have been characterized by difliculty in the manual actuation of the locking device because of its inaccessibility.

One object of the present invention is a drafting device of the character described, wherein the locking devices for the straight-edges are readily accessible for manipulation without moving the hand from the actuating knob on the protractor head.

The invention also has for one of its objects locking and stop mechanism for the protractor which may conveniently be actuated by either the thumb or a finger, as found most convenient, of the hand manipulating the knob to move the scale frame to the desired relative position. In carrying this aspect of the invention into effect, a rotatable wheel is preferably provided on the knob, which is movable in either direction to unlatch the straight-edges and permit them to be moved freely to any angular position but which, on release, will efiect locking of the protractor at the nearest even predetermined position.

Another object of the invention is to return the rotatable wheel on the knob to initial position whenever it is released by the operator. Accordingly. power is stored in power storing devices when the wheel is moved from initial position which is utilized to return the wheel.

The invention further seeks an instrumentalit transferring the rotary movement of the thumb or finger actuated devices to the latching devices for the protractor with a minimum number of parts to simplify assembly and to avoid the necessity for interlocking lever arms and other movement transferring devices.

The invention also resides in the details of construction by which the drafting device is made practical from the standpoint of ease and convenience in manufacture and durability and facility in use.

These and other objects of the invention and the means for their attainment will be more apparent from the following detailed description, taken in connection with the accompanying drawings illustrating one embodiment by which the invention may be realized, and in which:

Figure 1 is a diagrammatic view showing the drafting machine mounted on a drawing table;

Figure 2 is a view showing the head of the drafting device of this invention in vertical section;

Figure 3 is a fragmentary view of the drafting head in vertical section taken in the plane perpendicular to the plane of the section illustrated in Figure 2 and on the line 33 of Figure 2, looking in the direction of the arrows;

Figure 4 is a fragmentary transverse view taken in the plane indicated by the line 4--4 of Figure 2, looking in the direction of the arrows; and

Figure 5 is a plan view of the head, parts being removed to show details of construction.

Referring first to Figure 1, there is illustrated a typical endless band and pulley type of drafting machimfihconrprises'a'pafffif arms 6, 1 each comprised of tubes 8 within which an endless band 9 in each arm travels. The adjacent ends of the arms are pivoted together, as at It.

The free end of one arm is anchored, as at 12, to the side of a drafting board while the free end of the other arm is provided with a supporting head l4 comprising the knob or handle IS, a protractor l8 and frame means 20 supporting the straight-edges 22. Obviously the arms may assume any convenient structural shape.

As shown the tubes 8 extend into a frame member 24 comprising an outer flange 26 within which the pulley 28 turns. Inwardly of flange 28 is a cylindrical flange 30 concentric with the axis of the head. Rotatably mounted within the cylindrical flange 30, as by the ball races 32. 33 and ball bearings 34, is a cylindrical hub portion 35 which is integral with the pulley 28 and retains the bearing member 32 by means of a retaining ring 36 threaded to the upper end of the hub 35. Thus the pulley 28 is free to rotate within the frame portion 24 of the head without friction.

The pulley member 28 is rabbeted as at 38 to receive the protractor plate I8 and a locking plate 40 spaced from the protractor plate by a spacing ring 42. The locking plate 40 and the protractor I8 are fixed to the pulley by means of the screw or other securing means 45. Within the cylindrical hub 35 of the pulley is disposed a sleeve 44 functioning as a pivot pin and having its upper end of reduced diameter, as indicated at 46. so that a shoulder 48 is provided substantially flush with the upper surface of the pulley hub 35. The sleeve 44 is secured to, as by being made integral with, a plate-like bottom portion 50 to which the straight-edge supporting frame 20 is secured as by the screws 52.

The knob I6 is secured to the pivot pin 44 so that rotation of the knob I6 will rotate the straight-edge supporting frame 20 whenever that frame is released from the pulley by disengaging a common type of latch member 54 from the toothed latching plate 40, as will be understood. The knob I6 is operatively connected with the pivot pin in the following manner:

The knob I6 is recessed, as at 56, and receives a generally cylindrical or cup-shaped knobsupporting frame member 60-62 comprised of the cylindrical or annular wall 60 and a bottom wall 62 which extends beyond the circumferential margin of the wall 60 as a flange 63 to support a manually actuatable device I4 controlling the pawl 54 as hereinafter described. The knob I6 is secured to the wall 60 as by a screw 64 while the bottom wall 62 i keyed, as at 66, to the pivot pin 44 whereby rotary movement of the knob and frame member will turn the sleevelike pivot pin 44 and with it the straight-edge supporting frame 20. The bottom surface of the bottom wall 62 rests on a spacing ring 49 supported on shoulder 4 of pivot pin 44. The cup-shaped member 60-62 and pivot pin 44 are thus rotatable with respect to pulley 29.

The manually actuatable devices controlling the latch are carried by the knob above the level of the arm and in a position to be operated by the same hand of an operator as is used to grasp the knob. The upper end of the tubular pivot pin 44 is held in position by a nut 61 threaded on the upper end of the pivot member 44 and bearing against the bottom wall 62 of the cup-shaped member to retain it against the spacing ring 49 on shoulder 48. This nut member 61 is conveniently formed with an outwardly extending flange 68 to afford an enlarged supporting surface for latch actuating means. Thus the pulley 28 and knob frame 60-62 are held in assembly on the pivot member 44 by means of the disc-like portion 50 at its lower end and the nut-like member 61 at its upper end.

Surrounding the nut-like member 61 and within the cup-shaped frame member 60-62, is an annular member 69 of rectangular crosssection which rests upon the bottom 62 of the knob frame 6062 and is of an outside diameter to substantially fit within the cylindrical wall 60. This annular member 69 is shown (Figure 4) as having fixed on its upper surface, as by rivets 1|, an arcuately shaped piece or portion formed with a substantially rectangular tongue I2 extending radially from the annulus 68 and passing through an arcuate slot or cutaway portion I3 of wall 60. The cut-away portion of the wall subtends a substantial angle to permit suflicient arcuate movement to actuate the latching devices, as shortly to be described.

The annular manually actuated control member I4 is shown as having radially extending flns or finger engaging spokes I5 and is formed with a hub I6 which surrounds the wall and rests on flange 63 thereof. The tongue I2 enters a slot 18 (Figure 4) in the hub. The control memer I4 is thus positioned between the tongue I2 and the flange-like part 63 of the knob frame. Thus the annular manipulatable member I4 rotates on the peripheral surface of the frame member 60 and is held against vertical displacement.

The members 68, 69 support and actuate the actuating devices for the latch 54. As shown, the bore of the pivot tube 44 is formed, intermediate the ends thereof, with a constricted portion 82 having on its upper side a hemispherical supporting surface 84. The inner wall of the tubular member 44 from the aforesaid hemispherical surface progressively increases in diameter in a downward direction to form a substantially frusto-conical recess 86, as illustrated. Seated on the hemispherical bearing surface 84 is the enlarged spherical portion 88 of a rocking member or universally mounted lever, the lower extremity 80 of which terminates in a spherical end 94 disposed substantially below the plane of the lower end of the pivot pin 44 while the extremity 9| terminates in a spherical member 96 disposed above the plane of the upper surface of the nut-like member 61.

Reciprocable within the knob frame 60, 62 on the upper surface of the end of the tubular pivot pin 44 and the flange portion 68 of the nut-like member 61 is a, composite slide comprised of a block I00 formed with a recess I02 which receives the spherical end 96 of the universally mounted member and carries a superimposed elongated member I04 secured thereto as by a rivet I05 and a pin rivet I01 to extend beyond the end thereof and overlie that portion of the tongue I2 on the annular member 69 within the cut-away portion I3 in the frame wall 60. 0bviously, the composite slide I 00, I04 may be an integral member but is shown composite in the interest of manufacture.

In order to guide the slide I00. I04, a cupshaped member I22 is provided which is of a diameter equal to the internal diameter of the rabbeted portion I30 in the upper interior surface of the cylindrical wall 60 of the cup-shaped member 6063. The cup-shaped member I 22 rests upon the shoulder I90 of wall 60 and is formed in its bottom with a groove I26 extending in the direction of the longer axis of the slide I08 and dimensioned to receive and guide block I04 of composite slide I00I04 in the same vertical plane through which the end 94 of the swivel 90-9I is to move in reciprocating the slide I08 which actuates the latch 54. Cup-shaped member I22 is conveniently secured in position in the frame member 60 by a screw I23 (Figure 3), passing through the wall 60. Rivet pin I01 in the composite slide I00I04 is shown as extending through an elongated slot I24 running in the same direction as groove I26 in the cup-shaped member I22. Proximate the tongue I2 the cupshaped member I22 carries a post I21 to which one end of a spring I28 is connected. The other end of the sprin I28 is connected to the post I01 of the pin rivet passing through slot I24 and mounted on the composite slide I00I04.

The lowermost block member I00 is shown as having integral therewith laterally extending arms I06 on each side. These arms I06 lie in the J6 i ifilniufilptiai plane of the arcuate portion I on the rotatable member 69 so that when the member 69 is rotated in either direction by actuation of member 14, 15, one end or the other of the arcuate portion I0 will engage an arm I06 and move it to the left, as viewed in Figure 4, causing the composite slide I00, I04 guided in groove I26 to move to the left and thereby cause the end 9| of the swivel member to move similarly and to rock. In this movement, the arm 90 moves to the right and pushes the slide I08 to the right as viewed in Figure 2.

The composite slide I00I04 is therefore normally urged to latch engaged position but when the control member 14 is rotated and with it the slide actuating member 10, the slide I00, I04 guided in the groove I26 is retracted to the left in Figure 2 against the action of spring I28, thereby rocking swivel lever 90, 9I to release the latch. Upon release of the control member I4, the power storing means I28 causes the return of the slide I00I 04 and lever 90--9l to initial position.

The cooperating latching member is shown in greater detail in Figure as an angularly shaped lever 54 formed with a detent H0 at its one end. which is so shaped as to enter into and position itself in one of the recesses III of the latching plate 40. The other extremity of the pawl 54 is formed with an aperture II2 for reception on a in II3 mounted on the straight-edge supporting means 20. The lever 54 is urged toward the latch ing plate 40 by the engagement of a pin I I4 therewith, which pin H4 is carried by the end of the slide I08 slidable in a groove II5 formed in the frame and terminating proximate the end 94 of the oscillating lever 00, SI. Beneath the slide I08 is a lever H6 pivoted as at II'I to the frame 20 and secured as by pin I I8 to the slide I00. The free end II9 of this lever H6 is urged toward the axis of the pulley 28 by a power storing means shown as the coil spring I20 connected to the lever and to the frame 20.

In order to hold the straight-edge at points in termediate the registering position of the notches, a locking member I32 is provided which, since it is rarely used. is carried in the illustrated embodiment at a low point. as on the frame 20. Any convenient clamping lever or locking member may be provided within the purview of this invention and no further discussion thereof is deemed necessary.

The universal mounting of the lever within the tubular pivot pin facilitates manufacture and assembly, since the hemispherical seat within the tubular member is readily formed and it is merely necessary in assembly to insert the lever-like member 90, 9| into the upper end of the tubular pivot sleeve until the spherical portion of the lever rests upon the hemispherical seat. The coacting surfaces are easily formed whereby the lever 90, 9| may readily rock on the seat as on a fulcrum. The lever is constrained. in the illustrated embodiment, to rock in a plane including the axis of the pivot pin by reason of the fact that the upper end of the lever is received in the recess in the reciprocating slide. Obviously, the fulcrum of the lever may take other forms. For instance, the lever may be pivoted on a fulcrum pin passing through the tubular pivot pin in a direction perpendicular to the axis of the lever but the hemispherical seat and coacting spherical portion on the lever are preferred in the interest of simplicity of manufacture and facility in assembly.

The operation of the device is apparent from the foregoing description. Suffice it to say that a. draftsman may release the straight-edges by a slight rotation of the star wheel 14 with reference to the knob I6 by the thumb or finger of the same hand which engages the knob and without removing the hand from the knob. Rotation of annulus 14 in either direction carries with it the tongue I2 which in turn brings either end of the arcuate element I0 (depending on the direction of rotation) against one of the arms I06 of the slide and forces the arm to the left, as viewed in Figure 4, which results in bringing the composite slide I00, I04 against the action of the spring I28 toward the left as viewed and rocks the lever in a counter-clockwise direction to actuate the slide I08 and release the pawl 54. The knob and star wheel I4 are then turned simultaneously to adjust the straight-edges to the new angular position when the star wheel I4 is released permitting the parts of the locking instrumentalities to return to original position under the influence of the springs I20 and I28 and latching the frame 20.

Various modifications will occur to those skilled in the art in the composition, configuration and disposition of the component elements going to make up the invention as a whole as well as in the selection and combination of features to accomplish the results sought. and no limitation is intended by the phraseology of the foregoing description or illustrations in the accompanying drawings. except as indicated in the appended claims.

What is claimed is:

1. In a drafting machine, in combination, a supporting head adapted for free translatory movement over a drafting board comprising latching means, means for maintaining said latching means relatively fixed in orientation, straight-edge supporting means, pivot means rotatably supporting said straight-edge supporting means on said head, a knob on the pivot means, coacting latching means on said straight-edge supporting means, means mounting one of said latching means for movement into and out of engagement with the other latching means, power storing means normally urging said movably mounted latching means into engagement with the other latching means, rotatable control means carried by the knob. lever means movable with respect to said straight-edge supporting means and knob and extending therebetween, a slide carried by the knob, a cam carrying member actuated by the control means. a slide actuated by the cam for oscillating said lever between latch engaged and latch disengaged positions, said cam carrying member being rotatable in said knob and means for urging said slide to move said lever to latch engaged position.

2. In a drafting machine. in combination, a supporting head adapted for free translatory movement over a drafting board comprising latching means, means for maintaining said latching means relatively fixed in orientation. straight-edge supporting means. pivot means rotatably supporting said strai ht-edge supporting means on said head, a knob on the pivot means, coacting latching means on said straight-edge supporting means. means mounting one of said latching means for movement into and out of engagement with the other latching means, power storing means normally ur ing said movably mounted latching means into engagement with the other latching means, lever means supported for oscillatory movement relative to said straightedge supporting means and relative to said knob, a ball fixed on the lower end of said lever means, a slide secured to said movable latching means having an end adjacent said ball on the lever, a

slide engaging the other end of the lever, at least one arm on the slide, a rotatable member carried in the head, cam means carried by the rotatable member, a rotatable member on the head, operative connections between the two rotatable members whereby rotation of the second rotatable member will cause the cam means to engage an arm to move the slide and cause the lever to oscillate whereby rotation of said rotatable member is translated into sliding movement of the slide by the same hand of the operator as is used to grasp said knob, and said movable latching means is moved out of engagement in response to movement of said lever.

3. In a drafting machine, in combination, a supporting head adapted for free translatory movement over a drafting board comprising latching means, means for maintainin said latching means relatively fixed in orientation, straight-edge supporting means, pivot means rotatably supporting said straight-edge supporting means on said head, a knob on the pivot means, coacting latching means on said straight-edge supporting means, means mounting one of said latching means for movement into and out of engagement with the other latching means, power storing means normally urging said movably mounted latching means into engagement with the other latching means, lever means supported for oscillatory movement relative to said knob and relative to said straight-edge supporting means, means carried by said knob for moving said lever means comprising reciprocating means in operative relation to said lever, an annulus rotatably mounted in the knob, cam means on the annulus to engage and reciprocate the reciprocating means and an annulus rotatably mounted on the knob in a position to be moved by the same hand of an operator as is used to grasp said knob and connected to said first named annulus, and means coupling said movable latching means to said lever for moving said movable latching means out of engagement with said other latching means in response to movement of said lever.

4. In a drafting machine, in combination, a supporting head adapted for free translatory movement over a drafting board, comprising latching means relatively fixed in orientation, straight-edge supporting means pivotally supported for manual rotation relative thereto by a knob coupled to said straight-edge supporting means and disposed thereabove and having a device for securing said straight-edge supporting means against pivotal movement comprising a pawl mounted on said straight-edge supporting means for movement between a position engaging said straight-edge supporting means and a position disengaged therefrom, a pawl control device including a generally perpendicular lever pivoted at a midpoint for oscillatory movement relative to the axis of said head, means coupling said pivoted lever and pawl means positively to move said pawl between said engaged and said disengaged position comprising concentric annular members, a slide within the inner member operatively connected to the pivoted lever means, the outer concentric member being operatively connected to the inner member for synchronous rotation, means carried by the inner member to reciprocate the slide in one direction and power storing means tending to oppose reciprocation of the slide.

5. In a drafting machine, in combination, a supporting head adapted for free translatory movement over a drafting board comprising a latching plate, straight-edge supporting means, means for maintaining said latching plate relatively fixed in orientation, tubular pivot means rotatably supporting said straight-edge supporting means, a pawl, means mounting the pawl for movement into and out of engagement with the latching plate, power storing means normally moving the pawl into engagement with the latching late, a cup-shaped member secured to the pivot means and formed with a peripheral flange, a knob secured to the wall of the cup-shaped member in spaced relation to the flange, the wall of said cup being formed with an arcuately extending slot in spaced relation to the flange, an annular control member rotatably supported on the flange and formed with a slot, a slide having a portion extending into the arcuate slot and formed with a finger extending into the slot in the control member, a member carried by the cup-shaped member above the slide formed in its bottom with a groove to guide the slide and a slot, a pin on the member, a pin on the slide and passing through the slot in the member, power storing means between the pins to urge the slide in one direction, said tubular pivot means being formed inwardly with a hemispherical bearing surface, a lever member formed with a spherical portion seated in the bearing surface, one end of said lever member being received in a recess in the slide to oscillate the member, a slide engaged by the other end of the lever member and operatively connected with the pawl to move the slide to disengage the pawl from the latching plate when the lever member is oscillated.

6. In a drafting machine, in combination, a supporting head adapted for free translatory movement over a drafting board comprising latching means relatively fixed in orientation, straight-edge supporting means, tubular pivot means supported for manual rotation and coupled to said straight-edge supporting means and disposed thereabove and having a device for securing said straight-edge supporting means against pivotal movement comprising a pawl mounted on said right-edge supporting means for movement between a position engaging said latching means and a position disengaged therefrom, a pawl actuating device including a generally perpendicular lever pivoted at a midpoint supported for oscillatory movement within said tubular pivot means, means below the straightedge supporting means coupling said perpendicular lever and pawl positively to move said pawl between said engaged and said disengaged positions, a knob on the pivot means, power storing means tending to engage said pawl and means comprising an annulus to actuate the perpendicular lever disposed in a posltigh to be moved by the same hand of the operator as is used to grasp said knob.

7. In a drafting machine, means fixed in orientation, a straight-edge supporting frame, means for latching said frame to said member, a pivot pin having a generally tubular portion extending through said first named means and mounting said frame for rotary movement below said first named means, a knob fixed to said pivot pin above said first named means, a perpendicular lever member within the generally UUA U HL l (VAL 1 i uh lcm lb.

tubular portion of said pivot pin, mounting means within the tubular portion to support the lever member at a midpoint, reciprocating means above said first named means to oscillate said member, annular means to actuate the reciprocating means, and means below said first named means which actuates said latching means in response to oscillation of said member.

8. In a drafting machine, means fixed in orientation, a straight-edge supporting frame, means for latching said frame to said first named means, a pivot pin having a generally tubular portion extending through said first named means and mounting said frame for rotary movement below said first named means, a knob fixed to said pivot pin above said first named means, a lever member pivoted at a midpoint within the generally tubular portion of said pivot pin, reciprocating means within said knob to oscillate said lever member, means rotatable about said knob in both directions to move said reciprocating means, and means below said first named means which actuates said latching means in response to rotation in either direction of said rotatable means.

9. In a drafting machine, in combination, a supporting head adapted for free translatory movement over a drafting board comprising latching means, means for maintaining said latching means relatively fixed in orientation, straight-edge supporting means, a tubular pivot pin rotatably supporting said straight-edge supporting means, a knob on the pivot pin, coacting latching means on said straight-edge supporting means, means mounting one of said latching means for movement into and out of engagement with the other latching means, said tubular pivot pin being formed intermediate its ends with a constricted portion whereof the bore is formed with a substantially hemispherical bearing surface, lever means oscillating with respect to said straight-edge supporting means and knob and extending therebetween, said lever means being insertable in said tubular pivot pin from above and formed intermediate its ends with at least a hemispherical portion seated on said bearing surface, means adjacent said knob for oscillating said lever means, power storing means normally urging said means for oscillating said lever means for actuation of the other latching means, and mechanism for transmitting oscillating motion of said lever means into reciprocating motion of said movable latching means.

10. In a drafting machine, in combination, a supporting head adapted for free translatory movement over a drafting board comprising latching means, means for maintaining said latching means relatively fixed in orientation, straight-edge supporting means, pivot means rotatably supporting said straight-edge supporting means, a knob on the pivot means, coacting latching means on said straight-edge supporting means, means mounting one of said latching means for movement into and out of engagement with the other latching means, lever means oscillating with respect to said straight-edge supporting means and knob and extending therebetween substantially perpendicular to the plane of movement of said head, annular means adjacent said knob, a slide actuated by said annular means upon rotation thereof for oscillating said lever means, power storing means normally urging said slide to oscillate said perpendicular lever means for actuation of the other latching means,

UV"! VII and mechanism for transmitting oscillating motion of said lever means into reciprocating motion of said movable latching means.

11, I a, drafting machine, in combination, a supporting head adapted for free t ans ato y movement over a drafting board comprising latching means, means for maintaining said latchin means relatively fixed in orientation, straightedge supporting means, pivot means rotatably supporting said straight-edge supporting means on said head, a knob on the pivot means, coacting latching means on said straight-edge supporting means, means mounting one of said latching means for movement into and out of engagement with the other latching means, power storing means normally urging said movably mounted latching means into engagement with the other latching means, lever means substantially perpendicular to the plane of movement of said head supported for oscillatory movement, annular means carried by said knob and engageable at any point on its periphery I01 manipulation by the same hand of an operator as is used to grasp said knob and coupled to oscillate said lever means, and means mterengagmg said movable latcmng means and said lever means for moving said movable latching means out of engagement with me other latcmng means in response to oscillatory motion of said lever means.

12. in a drafting machine, in combination, a su porting Lita. aluktphcfl 101' Ilt-l'b' 'il'wbliawly movement over a draitmg board comprising latening means, means for maintaining said latching means relatively fixed in orientation, straightedge supporting means, pivot means rotatably supporting said straight-edge supporting means on said head, a knob on the pivot means, coactmg latcmng means on said straight-edge supporting means, means mounting one of said latching means for movement into and out of engagement with the other latcnmg means, power storlllg lllealls nor luau; ulglilg salu. illvvauly illuullted. latching means into engagement with the other latcmng means, lever means substantially perpendicular to the plane of movement of said head mounted for osciuatory movement, rotatable means carried by said pivot means and disposed ad acent said knob in a position to be moved by the same hand of an operator as is used to grasp said knob, means coupling said rotatable means and said perpendicular lever to oscillate said lever, and means coupling said movable latching means to said perpendicular lever for moving said latcmng means out or engagement with said other latching means in response to movement of said perpendicular lever.

13. In a drafting machine, in combination, a supporting head adapted for free translatory movement over -a drafting board comprising latcmng means, means for retaining said latching means relatively fixed in orientation, straightedge supporting means, pivot means rotatably supporting said straight-edge supporting means on said head, a knob on said pivot means, coacting latching means on said straight-edge supporting means, means mounting one of said latching means for movement into and out of engagement with the other latching means, power storing means normally urging said movably m n ed latching means into engagement with the other latching means, lever means substantially perpendicular to the plane of movement of said head supported for oscillatory movement an annular groove in said knob, an annulus operatively connected to said perpendicular lever means and rotatable in said groove for manually moving said perpendicular lever means, and means coupling said movable latching means to said perpendicular lever means for moving said movable latching means out of engagement in response to movement of said perpendicular lever.

14. In a drafting machine, a member fixed in orientation, a straight-edge supporting frame, means for latching said frame to said member, a pivot pin having a generally tubular portion extending through said member mounting said frame for rotary movement below said member, a knob fixed to said pivot pin above said member, a lever within the generallytubular portion of said pivot pin mounted to rock about an axis perpendicular to the axis of said pivot pin, annularly rotatable means adjacent the knob to rock said lever, and means below said member for positively actuating said latching means in response to rocking of said lever.

15. In a, drafting machine, a member fixed in orientation, a straight-edge supporting frame. means for latching said frame to said member, a pivot pin having a generally tubular portion extending through said member mounting said frame for rotary movement below said member, a knob fixed to said pivot pin above said member, a lever mounted to rock within the generally tubular portion of said pivot pin, rotatable means adjacent the knob to rock said lever, and means below said member for positively actuating said latching means in response to rocking of said 16 lever.

CARL W. KEUFFEL. HANS WIEDEMANN. ALBERT F. SHIELDS.

CERTIFICATE OF CORRECTION.

Patent No. 2,577,128. June 5, 1.915.

CARL W. KEUFFEL, ET AL. I

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 11,0, for "shoulder L read -shoulder L B"; page 1;, second column, line 51, claim 6, for "right-edge" read --strai'ght-edge--; page 5, second column, strike out the illegible portion of claim-l2, lines 50 to 11.21 inclusive, and insert instead the following -.supporting head adapted for free translator-y movement over a drafting board comprising latching means, means for maintaining said latching means relatively fixed in orientation, straight-edge supportingmeans, pivot means rotatably supporting said straight-edge supporting means on said head, a knob on the pivot means, 00-

acting latching means on said straight-edge supporting means, means mounting one of said latching means for movement into and out of engagement with the other latching means, power storing means normally urging said movably mounted;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 25th day of September, A. D. 1915.

Leslie Frazer (Seal) First Assistant Commissioner of Patents. 

